Extending twin and earth

[mjtefc9]

Hi all,

Trainee here.. just wanted to ask a question. Wall being knocked through and made into a door into the garage.

There is a radial 2.5mm in the way and some 1.5mm lighting circuit.

So I need to extend the cables to get them out the way.

Am I okay jointing with a maintenance free JB? I'll make sure it's more than 50mm from the plasterboard also.

I have to move the alarm pad aswell ‍ is that easy to do?

Thanks

Mark

 

[blup]

Crimp and shrink like this?:

How To Permanently Join a Cable - YouTube

Blup

 

[ericmark]

I would agree, same method as used for under ground cables seems best option, and neatest, although it seems maintenance free boxes are allowed.

What we should do, and what we do do, are not the same, we should to start with measure the loop impedance, and work out if cable can be added without exceeding the earth loop impedance or volt drop, in real terms we look at the installation and judge if we are likely to be near the limits, and if we think likely well within we only test after the install.

However I have been caught out, lucky for me I had raised the issue telling my boss I thought cable being used was too small, and since an in house job, cable was renewed without upper management realising we had made an error.

Today we are getting more and more EICR's done, so there is more and more chance of errors being found out.

 

[sparkwright]

Maintenance free junction boxes perfectly acceptable, and by far the simplest solution.

 

[mjtefc9]

Thanks everyone...

I like the heat shrink idea, but I've got a few maintenance free JBs here.. as long as that's fine I'll go with that. The cable is up in the ceiling so heat shrink would be a pain..

 

[sparkwright]

Crimp and shrink like this?:

How To Permanently Join a Cable - YouTube

Blup

Not a bad video.

Australian or something.

However, I like the bit at around 10 mins 25 secs when he burns a hole in the cable and tries to hide it .

 

[mjtefc9]

Not a bad video.

Australian or something.

However, I like the bit at around 10 mins 25 secs when he burns a hole in the cable and tries to hide it .

I saw that

 

[ericmark]

My old text book from collage some 50 old years ago shows using a Western role method, things have moved on, saw the first push fit connectors back in 1980 working for a Dutch company in Algeria, so they have been around for some 40 years, however so have the screw on springs and I am not in favour of those things.

To my mind the staggered joint with crimps and epoxy lined heat shrink providing one uses good crimps, is still a good joint.

But still don't like hiding joints where I can help it, I remember in the Falklands my boss saying the power use did not add up, generator producing around 250 kVA and the three installations using 70 kVA each so 40 kVA seemed to be missing, not exact as power use did vary, but some thing seemed wrong.

I said we had done some cable joints, but remembering where was another thing, however our luck was in, it snowed that night, so we dug where the snow had melted. Seems some one used denso tape.

 

[mjtefc9]

My old text book from collage some 50 old years ago shows using a Western role method, things have moved on, saw the first push fit connectors back in 1980 working for a Dutch company in Algeria, so they have been around for some 40 years, however so have the screw on springs View attachment 259869 and I am not in favour of those things.

To my mind the staggered joint with crimps and epoxy lined heat shrink providing one uses good crimps, is still a good joint.

But still don't like hiding joints where I can help it, I remember in the Falklands my boss saying the power use did not add up, generator producing around 250 kVA and the three installations using 70 kVA each so 40 kVA seemed to be missing, not exact as power use did vary, but some thing seemed wrong.

I said we had done some cable joints, but remembering where was another thing, however our luck was in, it snowed that night, so we dug where the snow had melted. Seems some one used denso tape.

So are you saying use good maintenance free junction boxes??

 

[bernardgreen]

Also he was not restricted by the cable being in situ and hence difficult to get access to.

 

[ericmark]

So are you saying use good maintenance free junction boxes??

I am saying you use your experience and decide best option in that situation, be it crimp, epoxy resin, either in a box or shrink sleeve, even soldered if not relying on solder for mechanical strength, or push in connectors, they are all classed as maintenance free and you select which is best where you are working.